<?php
/*

 Copyright (c) Ampache.org
 All rights reserved.

 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU General Public License v2
 as published by the Free Software Foundation.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
/* Make sure they aren't directly accessing it */
if (INIT_LOADED != '1') { exit; }

/**
 * Dba
 * This is the database abstraction class
 * It duplicates the functionality of mysql_???
 * with a few exceptions, the row and assoc will always
 * return an array, simplifying checking on the far end
 * it will also auto-connect as needed, and has a default
 * database simplifying queries in most cases. 
 */
class Dba { 

	public static $stats = array('query'=>0); 

	private static $_default_db;
	private static $_sql; 
	private static $config; 

	/**
	 * constructor
	 * This does nothing with the DBA class
	 */
	private function __construct() { 

		// Rien a faire

	} // construct

	/**
	 * query
	 * This is the meat of the class this does a query, it emulates
	 * The mysql_query function
	 */
	public static function query($sql) { 
		
		// Run the query
		$resource = mysql_query($sql,self::dbh()); 
		debug_event('Query',$sql,'6');
		
		// Save the query, to make debug easier
		self::$_sql = $sql; 
		self::$stats['query']++; 

		// Do a little error checking here and try to recover from some forms of failure
		if (!$resource) { 
			switch (mysql_errno(self::dbh())) { 
				case '2006': 
				case '2013': 
				case '2055': 
					debug_event('DBH','Lost connection to database server, trying to re-connect and hope nobody noticed','1'); 
					self::disconnect(); 
					// Try again
					$resource = mysql_query($sql,self::dbh()); 
				break;
				default:
					debug_event('DBH',mysql_error(self::dbh()) . ' ['. mysql_errno(self::dbh()) . ']','1'); 
				break; 
			} // end switch on error #
		} // if failed query

		return $resource; 

	} // query

	/**
	 * read
	 * This is a wrapper for query, it's so that in the future if we ever wanted
	 * to split reads and writes we could
	 */
	public static function read($sql) { 

		return self::query($sql); 

	} // read

	/**
	 * write
	 * This is a wrapper for a write query, it is so that we can split out reads and
	 * writes if we want to 
	 */
	public static function write($sql) { 

		return self::query($sql); 

	} // write

	/**
	 * escape
	 * This runs a escape on a variable so that it can be safely inserted
	 * into the sql 
	 */
	public static function escape($var) { 

		$string = mysql_real_escape_string($var,self::dbh()); 
		
		return $string; 

	} // escape

	/**
	 * fetch_assoc
	 * This emulates the mysql_fetch_assoc and takes a resource result
	 * we force it to always return an array, albit an empty one
	 */
	public static function fetch_assoc($resource) { 

		$result = mysql_fetch_assoc($resource); 

		if (!$result) { 
			return array(); 
		} 

		return $result;

	} // fetch_assoc

	/**
	 * fetch_row
	 * This emulates the mysql_fetch_row and takes a resource result
	 * we force it to always return an array, albit an empty one
	 */
	public static function fetch_row($resource) { 

		$result = mysql_fetch_row($resource); 

		if (!$result) { 
			return array(); 
		} 

		return $result; 

	} // fetch_row

	/**
	 * num_rows
	 * This emulates the mysql_num_rows function which is really
	 * just a count of rows returned by our select statement, this
	 * doesn't work for updates or inserts
	 */
	public static function num_rows($resource) { 
		
		$result = mysql_num_rows($resource); 
		
		if (!$result) { 
			return '0'; 
		} 

		return $result;
	} // num_rows 

	/**
	 * finish
	 * This closes a result handle and clears the memory assoicated with it
	 */
	public static function finish($resource) { 

		// Clear the result memory
		mysql_free_result($resource); 

	} // finish

	/**
	 * affected_rows
	 * This emulates the mysql_affected_rows function
	 */
	public static function affected_rows($resource) { 

		$result = mysql_affected_rows($resource); 

		if (!$result) { 
			return '0'; 
		} 

		return $result; 

	} // affected_rows

	/**
	 * _connect
	 * This connects to the database, used by the DBH function
	 */
	private static function _connect($db_name) { 

		if (self::$_default_db == $db_name) { 
			$username = Config::get('database_username'); 
			$hostname = Config::get('database_hostname'); 
			$password = Config::get('database_password'); 
			$database = Config::get('database_name'); 
		} 
		else { 
			// Do this later
		} 


		$dbh = mysql_connect($hostname,$username,$password); 
		if (!$dbh) { debug_event('Database','Error unable to connect to database' . mysql_error(),'1'); } 
			
		$data = self::translate_to_mysqlcharset(Config::get('site_charset'));

		if (function_exists('mysql_set_charset')) { 
			if (!$charset = mysql_set_charset($data['charset'],$dbh)) { 
				debug_event('Database','Error unable to set MySQL Connection charset to ' . $data['charset'] . ' this may cause issues...','1'); 
			} 
		} 
		else { 
			$sql = "SET NAMES " . mysql_real_escape_string($data['charset']); 
			$charset = mysql_query($sql,$dbh); 
			if (mysql_error($dbh)) { debug_event('Database','Error unable to set MySQL Connection charset to ' . $data['charset'] . ' using SET NAMES, you may have issues','1'); } 

		}
		if (!$charset) { debug_event('Database','Error unable to set connection charset, function missing or set failed','1'); }  

		$select_db = mysql_select_db($database,$dbh); 
		if (!$select_db) { debug_event('Database','Error unable to select ' . $database . ' error ' . mysql_error(),'1'); } 
		
		if (Config::get('sql_profiling')) {
			mysql_query('set profiling=1', $dbh);
			mysql_query('set profiling_history_size=50', $dbh);
			mysql_query('set query_cache_type=0', $dbh);
		}
		return $dbh;

	} // _connect

	/**
	 * show_profile
	 * This function is used for debug, helps with profiling
	 */
	public static function show_profile() {

		if (Config::get('sql_profiling')) {
		    print '<br/>Profiling data: <br/>';
		    $res = Dba::query('show profiles');
		    print '<table>';
		    while ($r = Dba::fetch_row($res)) {
		      print '<tr><td>' . implode('</td><td>', $r) . '</td></tr>';
		    }
		    print '</table>';
		}
	} // show_profile

	/**
	 * dbh
	 * This is called by the class to return the database handle
	 * for the specified database, if none is found it connects
	 */
	public static function dbh($database='') { 

		if (!$database) { $database = self::$_default_db; } 

		// Assign the Handle name that we are going to store
		$handle = 'dbh_' . $database;
		
		if (!is_resource(Config::get($handle))) { 
			$dbh = self::_connect($database);
			Config::set($handle,$dbh,1); 
			return $dbh;
		} 
		else { 
			return Config::get($handle); 
		} 


	} // dbh

	/**
	 * disconnect
	 * This nukes the dbh connection based, this isn't used very often...
	 */
	public static function disconnect($database='') { 

		if (!$database) { $database = self::$_default_db; } 

		$handle = 'dbh_' . $database; 

		// Try to close it correctly
		mysql_close(Config::get($handle)); 

		// Nuke it
		Config::set($handle,false,1); 

		return true; 

	} // disconnect

	/**
	 * insert_id
	 * This emulates the mysql_insert_id function, it takes
	 * an optional database target
	 */
	public static function insert_id() { 

		$id = mysql_insert_id(self::dbh()); 
		return $id; 

	} // insert_id

	/**
	 * error
	 * this returns the error of the db
	 */
	public static function error() { 

		return mysql_error(); 

	} // error

	/**
	 * auto_init
	 * This is the auto init function it sets up the config class
	 * and also sets the default database 
	 */
	public static function _auto_init() { 

		self::$_default_db = Config::get('database_name'); 

		return true; 

	} // auto_init

	/**
	 * translate_to_mysqlcharset
	 * This translates the specified charset to a mysqlcharset, stupid ass mysql
	 * demands that it's charset list is different!
	 */	
	public static function translate_to_mysqlcharset($charset) { 

                // MySQL translte real charset names into fancy smancy MySQL land names
                switch (strtoupper($charset)) {
                        case 'CP1250':
                        case 'WINDOWS-1250':
                                $target_charset = 'cp1250';
                                $target_collation = 'cp1250_general_ci';
                        break;
                        case 'ISO-8859':
                        case 'ISO-8859-2':
                                $target_charset = 'latin2';
                                $target_collation = 'latin2_general_ci';
                        break;
                        case 'ISO-8859-1':
			case 'CP1252':
                        case 'WINDOWS-1252':
                                $target_charset = 'latin1';
                                $target_collation = 'latin1_general_ci';
                        break;
                        case 'EUC-KR':
                                $target_charset = 'euckr';
                                $target_collation = 'euckr_korean_ci';
                        break;
                        case 'CP932':
                                $target_charset = 'sjis';
                                $target_collation = 'sjis_japanese_ci';
                        break;
                        case 'KOI8-U':
                                $target_charset = 'koi8u';
                                $target_collation = 'koi8u_general_ci';
                        break;
                        case 'KOI8-R':
                                $target_charset = 'koi8r';
                                $target_collation = 'koi8r_general_ci';
                        break;
                        default;
                        case 'UTF-8':
                                $target_charset = 'utf8';
                                $target_collation = 'utf8_unicode_ci';
                        break;
                } // end mysql charset translation

		return array('charset'=>$target_charset,'collation'=>$target_collation); 

	} // translate_to_mysqlcharset

	/**
	 * reset_db_charset
	 * This cruises through the database and trys to set the charset to the current
	 * site charset, this is an admin function that can be run by an administrator
 	 * this can mess up data if you switch between charsets that are not overlapping
	 * a catalog verify must be re-run to correct them
	 */
	public static function reset_db_charset() { 

		$translated_charset = self::translate_to_mysqlcharset(Config::get('site_charset')); 
		$target_charset = $translated_charset['charset']; 
		$target_collation = $translated_charset['collation']; 

		// Alter the charset for the entire database
		$sql = "ALTER DATABASE `" . Config::get('database_name') . "` DEFAULT CHARACTER SET $target_charset COLLATE $target_collation"; 
		$db_results = Dba::query($sql); 

                $sql = "SHOW TABLES";
                $db_results = Dba::query($sql);

                // Go through the tables!
                while ($row = Dba::fetch_row($db_results)) {
                        $sql = "DESCRIBE `" . $row['0'] . "`";
                        $describe_results = Dba::query($sql);

			// Change the tables default charset and colliation
			$sql = "ALTER TABLE `" . $row['0'] . "`  DEFAULT CHARACTER SET $target_charset COLLATE $target_collation"; 
			$alter_table = Dba::query($sql); 
	
                        // Itterate through the columns of the table
                        while ($table = Dba::fetch_assoc($describe_results)) {
                                if (strstr($table['Type'],'varchar') OR strstr($table['Type'],'enum') OR strstr($table['Table'],'text')) {
                                        $sql = "ALTER TABLE `" . $row['0'] . "` MODIFY `" . $table['Field'] . "` " . $table['Type'] . " CHARACTER SET " . $target_charset;
                                        $charset_results = Dba::query($sql);
                                        if (!$charset_results) {
                                                debug_event('CHARSET','Unable to update the charset of ' . $table['Field'] . '.' . $table['Type'] . ' to ' . $target_charset,'3');
                                        } // if it fails
                                } // if its a varchar 
                        } // end columns

                } // end tables


	} // reset_db_charset

} // dba class

?>
